Bone implants have been used to solve healthcare problems of orthopedic and maxillofacial reconstruction, prosthesis and denture fixation, and fracture stabilization. Additionally, bone implants have been developed to advance the knowledge of bone healing and remodeling as well as the interaction of bone and implant material or devices.
The osseous infusion capability of an implant system builds on the use of long bones, especially the sternum, for acute access to the cardiovascular system. Later, tibial and sternal routes were used for access to the vascular system in children and adults. Historically, a wide range of fluids have been infused (blood, serum, saline, etc.). In a review of 4359 attempted infusions; 89 were complete failures, 27 incidences of osteomyelitis occurred, and 10 other complications were reported (Rosetti et al., A Emer Med 14.9;103-105, 1985).
U.S. Pat. No. 4,772,261 relates to an intramedullary catheter containing a tubular conduit portion and a head portion; the conduit is elongated and needle-like to define a passage. A seal mechanism is intermitted into a cavity in the head portion, the seal mechanism includes a silastic self-sealing membrane. U.S. Pat. No. 4,936,851 relates to an analytic bone implant for obtaining new bone growth for histologic and morphometric analysis. U.S. Pat. No. 4,880,006 relates to a bone ingrowth chamber for studying bone ingrowth in an implant in response to locally administered test substances of different types. The ability to obtain a biopsy of cortical bone or cancellous tissue following complete healing and mineralization of this tissue is severely compromised by the design of the chamber as set forth therein.
A cancellous access port biopsy apparatus, which is a three-component titanium alloy device consisting of a cap, tissue basket, and basket end plate, has been described (Fox, WC, "Osseous Implants for Experimental Studies of Bone, Marrow, and Materials Biocompatibility," Dissertation, The University of Texas at Austin, May 1991).
Deficiencies in prior art bone implants include: i) blockage due to dead space in conduits or cavities, ii) microbial colonization, iii) exfoliation of the implant, iv) difficulty in surgical placement, v) a prior art conduit is not fabricated from materials such as titanium that have an affinity for bone because, for example, titanium will conduct bone into the conduit and block infusion, vi) failures of the mechanism, vii) the inability to acquire a biopsy, and viii) the inability to replace a sealing means or clear the device without explantation. Explantation of the device generally damages the surrounding bone, leaving the site unsuitable for future use. Because these prior art devices and techniques are not completely satisfactory, the present inventor has searched for improvements and provides the invention described herein.